'That's the scariest thing': Roger Penske, IndyCar investigating cause of loose wheel in 500

INDIANAPOLIS – Roger Penske wasted no time taking his typical hands-on approach to get to the bottom of why Kyle Kirkwood’s left rear wheel detached from the No. 27 Honda and flew over the top of the eastern edge of the Turn 2 grandstands with under 20 laps to go in Sunday’s Indianapolis 500. The Andretti driver ran into the spinning car of Felix Rosenqvist for a hit that, Kirkwood said, delivered 80 Gs.

Between taking part in Josef Newgarden’s ‘winner’s photo shoot’ on the Yard of Bricks at the Indianapolis Motor Speedway, talking to reporters (including the IndyStar) and chatting with his Penske Entertainment Corp. management team, Penske made a point to speak with Dallara’s founder and owner Gian Paolo Dallara and its Dallara USA CEO Stefano dePonti to about the mechanical failure.

Dallara is IndyCar’s longtime exclusive chassis manufacturer dating to 2012, and many of its employees were at IMS Monday morning to take photos with the winner of the Greatest Spectacle in Racing.

“I talked to the Dallara guys, and we’re going to look at it. We have tethers on those (wheels), and I’ve never seen a wheel come off of those. That, to me, is probably the scariest thing, and we’ve got to fix that so it doesn’t happen again,” Penske told select media. “Our technical guys are going to have a look at it.”

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IndyCar investigating cause of loose wheel

That morning, Penske noted he believed the tether attached to the left-rear of Kirkwood’s car had failed. IndyCar later confirmed in a statement to IndyStar that the rear tethers − which the series both strengthened and shortened the lifespan of from three years to two this offseason − remained intact.

Kirkwood told IndyStar on Monday on the red carpet for the 500 Victory Banquet that the car’s left-rear upright assembly “shredded” upon impact with the No. 6 Arrow McLaren Chevy. The upright serves as a major connection point between the wheel hub/wheel and the car’s suspension, pushrod and steering arm. The wheel tethers run parallel to the suspension pieces and connect in similar spots on both the chassis and the upright.

Constructed from woven strands of Zylon (the same material used in sheet form to protect the sides of the chassis from cockpit intrusions), this year’s new rear-wheel tethers contain a 60% increase in fiber count and are made to withstand forces over 22,000 pounds. Original versions of the tethers were mandated in 1999 after a tire came loose during the Indy Racing League’s May, 1, 1999, race at Charlotte Motor Speedway, hopped a 15-foot fence and killed three spectators (and injured eight others). Later that month at IMS in preparation for the 500, several wheels came loose during practice crashes, dangerously bouncing around the track – one nearly coming back and landing on top of driver John Paul Jr. in one instance.

The year prior, a dislodged tire during CART’s July 26, 1998, race at Michigan International Speedway also made its way into the grandstands and killed three spectators, injuring six others. IMS’s last fan fatality came during the 1987 Indy 500, where a loose tire on the track was hit by a car and launched into the Turn 3 grandstands, striking Lyle Kurtenbach, who was seated in the top row of the K grandstand.

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“IndyCar is in possession of the tire involved in yesterday’s incident and has found that the tether did not fail,” IndyCar said in a statement to IndyStar, though it wouldn’t confirm Kirkwood’s belief of the damaged upright’s involvement in the crash. “This is an isolated incident, and the series is reviewing to make sure it does not happen again. We will share the results once complete.”

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Kirkwood’s left-rear wheel came free of his car with 17 laps to go when Rosenqvist, after being passed by Newgarden heading into Turn 1, got loose and drifted up into the marbles, eventually unable to avoid sliding into the Turn 1 outer SAFER barrier. His car ping-ponged against the wall but eventually came free, drifting down the track into a spin. Kirkwood drove up high in the south short-chute in attempt to avoid the collision, but Rosenqvist’s car, turned around facing the oncoming Andretti car, clipped the left-rear of Kirkwood’s car and sent him into a spin, simultaneously sending Kirkwood’s wheel at the point of contact flying.

The No. 27 Honda turned 180 degrees and smacked the outer wall with the left side, flipped upside down and skidded along the outside of the track. The flying wheel sailed over the top of the catchfence and split the gap between the end of the Turn 2 grandstands and the Turn 2 suites. It landed on the front-left part of the white Chevy sedan’s hood, near the headlight, and ricocheted into a parked golf cart, where it came to rest in the parking lot.

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IMS told IndyStar Wednesday that Penske Entertainment will purchase the car’s owner, Robin Matthews, a new vehicle after track president Doug Boles welcomed her out onto the Yard of Bricks after the race and helped secure her a ride home Sunday.

An IMS spokesperson confirmed there were no injuries related to the wheel, though one spectator was hit by debris that flew into the stands and suffered minor injuries. That injured fan was later seen and released from the IMS infield care center.